Coupling



March 31, 193$. H. bDE-R I 2,036,084

COUPLING Filed Deb. 20, 1933 Inventor Hans Roder,

' HisA tovne g Patented Mar. 31, 1936 UNITED STATES PATENT OFFICE COUPLING Hans Roder, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York My invention relates to coupling'means and it has for one of its objects to provide improved means for coupling a plurality of circuits.

Another object of my invention is to provide an adjustable coupling system whereby the reactance of each of the difierent circuits intercoupled is maintained constant irrespective of variations in the degree of coupling between the circuits.

Another object of the invention is to provide a variable coupling device whereby in response to a single manipulation of the operator, as by movement of a single element, the degree of capacitive coupling between a plurality of circuits 1.) is varied while the frequency characteristics of the individual circuits are maintained constant.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing in which Figs. 1, 2, 3 and 4 represents different embodiments of my invention.

Referring to Fig. 1 of the drawing, I have shown therein a coupling device comprising plates I, 2, and 3, plates I and 2 being connected between a pair of terminals 4, and the plates 2 and 3 being connected between a pair of terminals 5. The terminals 4 and 5 are shown for purposes of illustration as connected respectively to the tuned circuits l6 and I! which are to be intercoupled. For example, the output circuit of a radio transmitter may be connected across terminals 4 and an antenna may be connected to the terminals 5. The plates l, 2, and 3 are arranged in parallel relation, the plates l and 3 being spaced apart in broadside relation from the plate 2. Interposed between plate 2 and plates land 3 is a third plate 6. This plate is arranged for reciprocal movement as indicated by the rack l which is connected thereto and which 4 cooperates with the gear 8. Upon rotation of the gear the plate 6 is moved upwardly and downwardly between plate 2 and plates l and 3.

In this way it will be observed that the circuit connected to the terminal 4 is coupled to the circuit connected to the terminals 5 by means of the common capacity which exists between plates 2 and 6. The circuit connected to terminals 4 includes the capacity between the plates l and 6, and similarly the circuit connected to the terminals 5 includes. the capacity between the plates 3 and 6, these capacities being individual to the respective circuits. Plates l and 3 are shown as arranged in a common plane so that corresponding variations in these individual capacities occur upon movement of the plate 6. It can now be very readily shown, algebraically, that if plates I, 2, and 3 be constructed of equal area the capacitances between plates I and 2 and 2 and 3 will be constant irrespective of the position of the plate 6. This means of course that the common capacity, that is, the capacity between plates 2 and 6, which is common to the two circuits, may be varied over a wide range without any variation in the reactances of the circuits connected to the opposite pairs of terminals 4 and 5.

In Fig. 2, I have shown a cliiierent embodiment of my invention in which the coupling device comprises a pair of capacitance potentiometers, one of these potentiometers comprising condensers 9 and I4 connected in series, and the other comprising condensers 9l3, the first of these potentiometers being connected between the terminals 4 and the other being connected between the terminals 5 through a variable portion on the other potentiometer, this variable portion thus being common to the two circuits to be intercoupled. Corresponding condensers 9 and 9; l0 and I0, etc., in the two potentiometers are of equal value although the individual condensers in each potentiometer may be of varying value, as for example of graduated values. Corresponding positions on the two p0- tentiometers are arranged to be interconnected by means of a switch [5 which is arranged for reciprocal movement over a pair of banks of contacts, the contacts of each bank being connected to points between the difierent condensers in the respective potentiometers.

It will be seen that by movement of this switch the portion of the potentiometer 9, Ill-l4 which is common to both of the intercoupled circuits is varied thereby varying the degree of coupling between the two circuits. Thus in the position shown condensers I2, 13, and I4 are common to the two circuits whereas condensers 9, l0, and H are connected in one of the circuits and the impedances 9', l0, and II are connected in the opposite circuit. By movement of the switch l5 upward the impedance ll of the potentiometer 9, Ill-44' is included in the portion common to the two circuits while the impedance H. is removed from the circuit connected to the terminals 5. Similarly, if the switch member be moved downward from the position shown the impedance i2 will be removed from the common portion and incorporated into the individual circuit connected to the terminals 4, and similarly the impedance l2 will be included in the individual circuit connected to the terminals 5. As thus arranged it will readily be seen that the total impedance between the terminals of either of the pairs 4 and 5 is constant irrespective of the position of the switch. Thus the switch [5 may be utilized to vary the coupling between the two circuits over a very wide range without changing the reactance of either circuit.

While in Fig. 2, I have shown the various impedances 9, I0, etc. and 9, III, etc. as condensers, it will of course be understood that this is by way of illustrating what I believe to be the preferred and most useful embodiment of the invention, and that these impedances may be inductive, or resistive, as shown respectively in Figs. 3 and 4.

w The utility of my invention as represented in Figs. 1 and 2 will be apparent to a person skilled in the art of radio transmitters, for example, where it is frequently desired to couple the tuned output circuit of a vacuum tube transmitter to a tuned antenna. Heretofore it has been necessary, in the process of tuning the antenna circuit and tube output circuit, and adjusting the coupling between these circuits properly to load the transmitter tube to effect a very large number of adjustments. This is due to the fact that each of the various adjustments aiiects each of the others thereby necessitating a series of alternate cut and try adjustments until the de sired condition is reached. To obtain best results a skilled operator is required. In accordance with my invention, for example, the two circuits may be uncoupled, as for example in Fig. 1 by moving the plate 6 in contact with the plate 2, or in Fig. 2 by moving switch l5 to its lowermost position. The condenser I4 is preferably of very large capacitance so that when the switch I5 is in its lowermost position the two circuits are substantially uncoupled. The two circuits may then be tuned independently of each other by variation of capacitance or inductance which may be included in them for that purpose and not shown in the drawing. The circuits are then coupled together by upward movement of the plate 6, or the switch l5. This adjustment does not afiect the tuning of either circuit because it does not affect the reactance of either circuit. Plate 6, or the switch I5, may then be moved to the position where desired loading of the transmitter is effected.

While I have shown particular embodiments of my invention it will of course be understood that I do not wish to be limited thereto since different modifications will readily occur to a person skilled in the art. I contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, a pair of tuned circuits to be coupled, each of said circuits including an individual variable reactance, a variable reactance common to both of said circuits, said common reactance being in series with both of said individual reactances, and means responsive to movement of a single movable element automatically to vary both of said individual reactances simultaneously with variation of said common reactance and by such amounts as to maintain the total reactance of said circuits constant whereby the frequency characteristics of said tuned circuits are unaffected by variation of coupling between said circuits while maintaining all elements of said circuits other than said common and individual reactances in constant condition.

2. In a coupling device, a capacitance comprising a pair of parallel plate electrodes spaced apart, a third parallel plate electrode spaced apart from one of said first mentioned plate electrodes and on the same side thereof as the parallel plates of equal area, an additional plate having an area equal to the area of each of said first plates and positioned parallel to said first plates in spaced apart relation thereto, and means comprising a movable plate interposed between said plurality of plates and said additional plate for varying the capacity between said movable plate and said additional plate without affecting the capacity between each of said plurality of plates and said additional plate.

4. In combination, a pair of impedance potentiometers, means to connect intermediate points on said potentiometers whereby a portion of the impedance of one potentiometer is in series with a portion of the other potentiometer, means to vary said connection along said potentiometers, said potentiometers being so proportioned relative to each other that the impedance between the outer terminal of said series connected portion of said one potentiometer and the opposite terminal of said other potentiometer is constant irrespective of the position of said connection on said potentiometers.

5. In a system for coupling a plurality of circuits, a plurality of series connected condensers in each of said circuits, each condenser in one circuit having capacitance equal to the capacitance of a corresponding condenser in another circuit, and means to connect a variable portion of the series connected condensers of one circuit in series with a variable portion of the series connected condensers of the other circuit whereby a portion of the series condensers in said one circuit are included in both circuits, said means being arranged to maintain constant the total series capacitance of the portion of said condensers common in the two circuits and the portion included only in said other circuit for all conditions of said means. 7

6. A plurality of coupled circuits, each of said circuits including a fixed shunt capacitance, and means to vary the coupling between said circuits while maintaining said shunt capacitances of fixed value, and all other elements of said circuits in constant condition, and at the same time maintaining the frequency characteristic of each of said circuits constant, said means comprising means to include a variable amount of both of said fixed shunt capacitances in a common portion of said circuits.

7. A plurality of coupled circuits, each of said circuits including a fixed shunt capacitance, and means to vary the coupling between said circuits while maintaining said shunt capacitances of fixed value, and all other elements of said circuits in constant condition, and at the same time maintaining the frequency characteristic of each of said circuits constant, said means comprising means to include a variable amount of both of said shunt capacitances in a common portion of both circuits, a single movable element, means to actuate said element, and means to include a variable amount of both of said shunt capacitances in a common portion 01' said circuits, said common portion being between said movable element and a terminal of each of said circuits.

HANS RODER.

CERTIFICATE OF CORRECTION.

Patent No. 2,036,084. March 51, 1956.

HANS RODER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 49, for "terminal" read terminals; and second column. line 21, for "and" first occurrence, read to; page 2, second column, line 1, claim 1 after "constant" insert a comma; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office Signed and sealed this 12th day of May, A. D. 1936.

Leslie Frazer (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 2,036,084. March 51, 1956.

HANS RODER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1 first column, line 49, for "terminal" read terminals; and second column, line 21 for "and" first occurrence, read to; page 2, second column, line 1, claim 1 after "c0nstant insert a comma; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office Signed and sealed this 12th day of May, A. D. 1936.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

